Method of heating semi-finished products

Abstract

A method involves heating fiber-reinforced semi-finished products of differing wall thickness to a required temperature above the glass transition range or the matrix melting temperature of a plastic matrix of the semi-finished product to be heated. In a first step, the semi-finished product to be heated is heated by thermal conduction to below the glass transition range or the matrix melting temperature. In a further step, the remaining amount of heat for reaching the required temperature above the glass transition range or the matrix melting temperature is introduced by thermal radiation or thermal convection.

The invention claimed is: 
     
       1. An apparatus for heating fiber-reinforced semi-finished products of differing wall thicknesses, the apparatus comprising:
 a first tool half having a first heatable base plate; and 
 a second tool half having a second heatable base plate, each of the semi-finished products to be arranged between the first tool half and the second tool half to be heated, 
 wherein at least one of the first tool half and the second tool half has a flexible thermal conduction layer adaptable to differences in wall thickness of the semi-finished products to be heated, the flexible thermal conduction layer being configured to transmit heat energy by thermal conduction to the semi-finished products to be heated, and 
 wherein the flexible thermal conduction layer is arranged on a surface of at least one of first heatable base plate of the first tool half and the second heatable base plate of the second tool half so as to be located on the surface of the at least one of the first heatable base plate of the first tool half and the second heatable base plate of the second tool half in both an open position and a closed position of first tool half and the second tool half. 
 
     
     
       2. The apparatus as set forth in  claim 1 , further comprising a pressing device for pressing the flexible thermal conduction layer against each of the semi-finished products to be heated so that the flexible thermal conduction layer bears against a surface of the semi-finished products to be heated. 
     
     
       3. The apparatus as set forth in  claim 2 , wherein the pressing device includes the first tool half and the second tool half movable relative to each other to generate a pressing effect. 
     
     
       4. The apparatus as set forth in  claim 1 , wherein the flexible thermal conduction layer is a vacuum mat configured to retain a shape by applying a vacuum thereto after the flexible thermal conduction layer has been applied to a surface of the semi-finished products. 
     
     
       5. The apparatus as set forth in  claim 1 , wherein the flexible thermal conduction layer comprises an elastomer. 
     
     
       6. The apparatus as set forth in  claim 5 , wherein the flexible thermal conduction layer comprises a silicone, and has fillers for increasing thermal conductivity. 
     
     
       7. A heating apparatus comprising a first heating station comprising the apparatus as set forth in  claim 6 , and a second heating station configured to heat by thermal radiation or thermal convection the semi-finished products pre-heated in the first heating station.